Telescopic apparatus



W v J. B. HENDERSON TELESCOPIC APPARATUS original Filed July 2 1919 5 Sheets-Shed 1 i 1318777 May 1927 J. a. HENDERSON TELESCOPID APPARATUS Original Filed July 26, 1919 3 Sheets-Sheet 2 Snow bo'c M '5. 3&1 L 61H 1;

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May 17, 1927.

J. B. HENDERSON TELESCOPIC APPARATUS Original Filed Jul 2 1919 7 s Sheets-Sheet 3 Patented May 17, 192 7.

UNITED STATES PATENT orrlcs.

JAMES BLACKLOOK HENDERSON, OF LEE, ENGLAND.

rnnnscorio arramrus.

Original application filed July 26, 1919;Ser1a1 No. 313,588, and in Great Britain larch 8, 1915. Divided and this application filed May 19, 1920. Serial 170. 382,678.

(GRANTED UNDER THE PROVISIONS 01 THE ACT OF MARCH 3, 1821, 41 STAT. L, 1313.)

This invention relates to optical instruments adapted for use on angularly moving platforms as onboard ship or on aircraft and the like.

The invention has for its primary object the provision of an optical instrument of this character in which the field of view will be stabilized irrespective of the angular motion of the platform upon which it rests.

,The invention has also for its object the provision of means for stabilizing the field of view by gyroscopic apparatus and for compensating for any straying of the gyro, by adjusting a part of the optlcal system or by adjusting the gyro or by making both drawings which cal instrument.

Figs. 3, 4:, and show side elevation, plan and front elevation of an alternative arrangement which embodies a method of optical compensation for the tilting of-the yro axis.

Fig. 6 shows plan of an alternative arrangement of fixing the reflectors.

Figs. 7, 8, 9 and show respectively front elevation, side elevation with the. gyro remalvhemploy.

moved, sectional plan and side elevation of the telescope of an arrangement which permits. the observer to face the target and which has optical compensation for the tiltin of the gyro axis. igs. 11, 12, 13, .14, and show various arrangements of optical systems which I e ro-rotor, casing 1 is suspended on a vertica trunnion axis 2 in the gimbal ring 3, which is suspended on the horizontal trunnion axis 4 in the outer casing 5 of the instrument. I preferably arrange the gyro to be in neutral equilibrium on the trunnion axis but may give a small gravitational stability to the combination of gyro, 1 and gimbal ring 3 about the trunnion axis 4.

The outer casing 5 may be supported on any suitable mounting on a ship or other angularly moving platform but for purposes of illustration it 1s shown mounted on avertical axis on the pedestal 6 with a worm 7 gearing in a worm wheel 8 for training the casin in .azimuth. The rotor casing 1 carries t e two reflectors 9 and 10 the planes of reflection of which are at right angles, are normally vertical and intersect in the axis of the trunnion 2. The objective 11 and eyepiece 12 are fixed to the case symmetrically about the centre line of the gyro in its central position, and the focal plane and the optical centre of the objective are arranged so that they are equidistant from the trunnion axis 4.

The observer sits with his back to the target with his eye to the eyepiece 12 and as explanation of the steadiness of the image is that when the objective 11 rises and falls the ima e of the target formed by the objective in t e focal 'lane rises and falls an equal amount, but t e image and cross wires on the focal plane also rise and fall by the same amount as the objective since they and the objective are equidistant from the axis 4. Hence angular motion about axis 4. does not affect the wires.

Any angular motion of the casing 5 about the rotor axis in its central position causes the objectiveto rise and the eyepiece to fall or vice versa) b equal amounts but. it

simultaneously inc ines the line of intersection of the two anirr'ors 9 and 10 .and the position ofthe image on the cross result is that the image of the target remains I on the cross wire but becomes slightly inclined to the vertical. An straying motion of the gyro about the vertical trunnion does not affect the position of the image on the cross wire but straying motion about the horizontal trunnion raises or, lowers the image of the tar et on the cross wire. The

gravitational st-a ility about the horizontal trunnion axis 4 is intended to prevent the straying from exceeding a small value. When the trunnion axis 2 it can be brought back to strays about the vertical the central iposition by means of a torque applied to t e end of the trunnion axis 4 which projects through the case 5 and may be furnished with a friction head 4 for that purpose. When it strays about the horizontal axis it can be brought back by means of impacts imparted to the rotor casing by turning the four pronged sprocket 13 by means of the knob 15, causing the spokes of the sprocket to engage with the light spring 14 which is attached to the rotor casing. These impulses may be applied to the rotor casing y any other suitable means, electrical or mechanical.

If the rotor axis deviates in azimuth from the central position the image of the tar et moves up and down by a small amount re atively to the cross wire with each roll and if the greatest accuracy of sighting is required, an alternating precession would have to be introduced to compensate for this motion. This compensation is more accurately done optically as shown in Figs. 3, 4 and 5. The optical compensation consists in mounting the objective 11 and eyepiece 12 on a plate which is pivoted on a pin 22 of the outer casing 5. The same compensation applies to any tilting of the gyro axis about the trunnion 4 and obviates the necessity of introducing a means of processing the gyro about theliorizontal trunnion.

If the gyro axis becomes tilted out of the horizontal plane by rotation about the trunnion 4, the image of the target is raised, let us say, on the cross wires. The superposition of the image again on the cross wires can be brought about by a corresponding lowering of the objective or a raising of the eyepiece-or a'comhination of both. This compensation is brought about by turning the plate 21 on the pin 22.

Fig. 6 shows. an alternative method of mounting the mirrors on the gimbal ring instead of on the gyro case, the mirrors 9 and 10 being attached to the gimbal ring 2-, by the two arms 27. Instead of being fixed to the gimbal ring they might equally well be carried on the horizontal trunnion 4, the obectlve and eyepiece being suitably arranged to correspond.

An objectionable feature of the constructions hereinbefore described is that the observer has his back towards the target. Figs. 7, 8, 9 and 10 illustrate respectively side elevation, back elevation, sectional plan and front elevation of an arrangement of parts which overcomes this objection and which has certain other advantages.

The rotor casing 1 is carried on' the vertical trunnion 2 in the gimbal ring 3 which is supported on the horizontal trunnion 4, at one end of the case 5 and at the othen end on the U shaped bracket 30. The outer case 5 is mounted upon a pedestal as in Fig. 1 or on any other convenient type of mounting. The objective 11 and eyepiece 12 of the telescope are rigidly attached to v the cylindrical sleeve 31 which can turn on the cylindrical projection 32 of the casing 5, suitable apertures being cut in the cylinder 32 to clear the beam of the telescope. The optical centre of the objective and the focal piane are equidistant from the centre of the cylinder but on opposite sides of the centre.

The telescope is of the ordinary type containing l'our ieflcctors as in prismatic binoculars. All four reflectors may be attached to the trunnion axis 4 but in the arrangement illustrated only two 33 and 34 (Fig. 9) are attached to the trunnion axis 4 by the crank arm 37, the line of intersection of the two planes oi rellcction being perpendicular to the trunnion axis. The other two reflectors and 36 (Figs. 9 and 10) are carried by the cranked arm 38 which is pivotally attached to the casing 5 by the pin it. The line of intersection of the planes of reflection of 35 and 36 is normally coaxial with the trunnion 4. The motion oi the cranked arm 38 about the pin 39 is controlled by a pin 40 attached to the arm engaging in a slot in the L shaped'lever 41 (Fig. 8) which turns on a boss 42 on the casing 5 concentric with the trunnion 4. The vertical arm of the L shaped lever is actuated by the screw 43 working in the nut 43, which is attached to the casing 5, pressing against the pin 44 which projects from the L shaped lever through a slotted hole in the casing 53. By turning the screw 43 the cranked arm 38 can be raised or lowered about the pin 39 and the two reflectors 35 and 36 are thus raised or lowered.

The image of the target can be elevated or depressed in the field of view by turning the screw 43. The image remains stationary on the cross wires so long as the gyro does not precessabout the horizontal trunnion 4. When the ship rolls so much that the beam from the target after passing through the objective misses the reflectors altogether so that the field of view isdark, the image of the target can easily be brought into the field again by turning the cylindrical sleeve 31 carrying the objective and eyepiece on the cylindrical projection of the casing 5, in opposite phase to the roll so as to keep the line joining the objective and eyepiece roughly horizontal. A quick motion once during each roll is equallyeffective.

The optical system illustiated in Figs. 2, 6 and 9 are not the only ones I may use. In general, I may use any telescopic system which gives an upright image, the inverting portion of the system being stabilized by the gyro and the various dimensions of the system being chosen so that the image remains stationary on the cross-wires. For example, I may employ a system like that illustrated in Figs. 11 and- 12. The objective and the eyepiece lenses 51 and 52 are attached to the telescope ring as in Fig. 9. The prism 53, a side elevation of which is illustrated in Fi 12, is stabilized by the gyro. The traveling achromatic prism 54 serves to keep the ob'ect on the cross-wires when the gyro-axis t1lts,the translation of the prism 54 parallel to the axis of the telescope being linked up to the screw 43 (Fig. 10) by suitable mechanical linkage.

Figs. 13 and 14.- show two elevations of another arran emcnt I may employ. The objective 55, t e eyepiece 56-57 and the ri htangled prisms 5S-59 move with the ship, wlule the right-angled prism is stabilized by the gyro. In order to compensate for'the tilting of the gyro-axis I-ma translate the prisms 58 and 59 and link it is translation with the screw 43 by suitable linkage.

Fig. 15 shows an arrangement I-may employ which contains no prisms or reflecting surfaces. The objective 61 and the eyepiece 6Q62 movewith the ship. The focal plane of 61' is at 63 and the. inverting lens or system of lenses 64, which is stabilized by the.

gyro, forms an uprightimage in the second focal plane 65. In order to compensate for the tilting of the yro-axis, I may attach the lens 64 to a cran 66 which normally turns about a crank-pin 67 co-axial with the gyrotrunnion and attached to the case 5 of the instrument. This crank is stabilized by the gyro by means of a pin 68 carried by 9.1

ual crank 66 mounted on the gyro truni nion 4' which is coaxial with the crank pin 67 the crank pin 68 engaging in a slot 69 in the crank 66. The pin 67 is attached to the lever 38 in Fig. 9 so that it can be moved up and dowiih hand. This arrangement of levers might e applied to the rism 53 in Fig. 11 to move up and down an thus to obviate the necessity of using the prism 54.

I claim 1. An optical instrument adapted for use on an angularly moving platform comprising a casing adapted to move with the platform, an optical system having, optical ele- '-of the movement of the system to said ments arranged to nullify the effect thereon platform, a gyrosco e having a horizonta axis of rotation, an means connecting a part of said optical ope whereby the said part may be sta llized.

2. An instrument adapted for use on an angularly moving platform comprising anoptical system, a gyroscope for stabilizing ,a part of said system, and means for adjustmg the gyroscope to compensate for its straying. g I

3. An instrument for use on an angularly moving platform comprising optical elements adapted to 1partake of 'the angular movement of the p atform, a gyroscope, an

"optical element connected to the gyrosco e' and movable relatively to the platform y tually the gyroscope to compensate for the effect of I.

form, an o tical system carried by the casing andinclu ng an inverting part, and gyroscopic apparatus controlling the inverting part of the system to stabilize the field of view.

5. An optical instrument adapted for use on an angularly moving platform comprising a casing adapted to move with the platform, an ontical system having an inverting part, a gyroscope having a horizontal trunnion axis, and means connecting the inverting part of the optical system to the horizontal trunnion axis whereby the said part may be stabilized.

6. An optical system comprising a lurality of parts, one of which is optica ly reversing, and a gyroscope controlling the optical reversing partot the system.

.7. In an apparatus of the type, described, an observation instrument mounted on a body subject to angular variations of position, an optical reversiiig member in optical relation to the observation instrument, stabilizing means free from forced oscillations in phase with the disturbing forces introduced by the oscillations of the body, and means for connecting said member and the stabilizing means whereby relative motion between the stabilizing means and the body is communicated to the member.

8. In an apparatus of the type described, an observation instrument mounted on a body subject to angular variations of position, an optical system in said instrument containing an optical reversing portion,"

' 9. An optical instrument for use on an angula'rly movin movement .of the body, an optical element mounted to move relatively to the body, a gyroscope mounted for movement about murpendicular axes, connections between t re gyroscope and the optical element for moving the latter relatively to the body to compensate for the efiectof the. angular movement thereof on the field of view of the instrument and means forcom nsating for the straying of thegyroscope a at its axes.

10. An optical instrument for use on an body, comprising optical elements adapts v to partake of the angular angularly moving body, comprising optical elements adapted to partake of the angular movement of the body. an optical element mounted to move relatively to the body, a gyroscope mounted for movement about mutually perpendicular axes, connections between the gyroscope and the optical element for moving the 'latter relatively to the body to compensate for the effect of the angular movement thereof on the field of View of the instrumentand means for applying torques to the gyroscope about each of its supporting axes to compensate for straying about the other axis.

11. An optical instrument for use on an angular-1y movingbody, comprising a casing adapted to partake of the angular movement of the body. optical elements adjustahly mounted on the casing. an optical element associated with the casing: and mounted to move relatively thereto. a gyroscope mounted for movement about mutually perpendicular axes, connections between the gyroscope and the optical element for moving the elementrelatively to the casing to compensate for the effect of the angular movement of the body on the field of view of the instrument and means for compensating for the straying ot' the gyroscope about its axes.

12. An optical instrument for use on an angularly moving body, comprising a casing adapted to partake of the angular movement of the body, and provided with a projection, a member movably mounted on the projection and carrying some of the optical parts of the instrument, an optical element;

movably mounted with respect to the easing. a gyroscope, means for mounting the gyroscope on the easingfor movement about. nmtuallypet-pendieular axcs,eonneetions between the optical element and the mounting means for moving, the element relatively to the casing to compensate for the effect of the angular movement of the body on the field of view of the instrument, a second optical element morably mounted on the casing and means for adjusting" the position of the second optical element with respect to the easmg.

JAMES BLACKLOCK HENDERSON. 

